skysight-inc/HackerNews huggingface dataset:
http://www.stanford.edu/class/cs276a/projects/docs/berkeleyd... describes the performance of BTree data structures in real world databases. (It is discussing a standalone key/value store, but the internals of a database index work the same way.)

As noted, 3 levels suffices for a moderate sized table, and it would be rare to need more than 5 levels. The "levels" in question are pages of memory that have to be looked at. The reason that this is less than you expect is that inside of each page you essentially have a tree that has several levels to traverse. However the time to traverse that tree is less than the time to fetch the next page, so the operations of concern are fetches of pages.

The most important number noted in that link is that under normal operation once caches are warmed up, it should a maximum of one disk seek to traverse the index. That single disk seek, if it happens, takes longer than all other operations.

The long and short of it is, "in theory log(n), in practice a reasonably small constant."
Is it more than just a blog/text? I'd like to see it since you claim it was "pretty easy."

I know a lot about how responsive design works and designing within those constraints, and I would say "pretty easy" is a huge understatement.
An Australian freeway has been shut down. 'Computer glitch' or chinese hack job?
Fourth request. Seems like a cool idea, but not cool enough for me to have to create an account on either of those two services.
And a fourth
i realize it might be slightly out of scope, and a less common use case, but an FTP integration that worked the other way around (users can upload to a filepicker hosted FTP and it sends a postback to my app) would be enough to get me to subscribe. cool service.
This actually would have a lot of value, if it were executed slightly differently.

Online trading markets are excellent at exposing 'insider information', but the prices have to be informed by (a) availability of stock and (b) the ability for traders to negotiate prices between themselves.

In this instance, the valuation is based on:

"...a simple formula to give each domain a daily price."

So, what does this achieve? It rewards the user(s) who can best approximate the formula, gather the requisite information and act on it. In other words, the best performers are those that can best emulate the workings of the site.

Ok, it is called "LinkDAQ" for a reason - but there is an opportunity here to build something linked to real value.

It would be better to seed initial stock values from such a formula, but then leave users to trade between them. Stocks "cash out" during [real] funding rounds, dividend payouts or difference in actual stock valuations. If you can refine the market sufficiently, you should have a reasonably informative prediction engine.

I've been a long time user of the iPredict prediction market in NZ (ipredict.co.nz) - but that's small biscuits next to InTrade, for example.
I've never actually posted any of my projects in the past. Every so often I wake up to an inbox flurry and then check HN :)
Coming from Java, I didn't understand the point of pointers (no pun intended) until I was re-reading through chapter 1 of K&R C.

At one point, they mention how when you pass a variable into a function, it only passes the value really, "copying" the variable, in a way. Then they go on to say that changing the original variable is talked about in chapter 5, which covers pointers. Then it just clicked. If you want to change the original value, pass a pointer to said variable. If you want to just use the value of a variable, pass the variable through the function.

It's so much easier than what I was doing before, assigning the variable to the return value of a function.
BTW when you order a Thinkpad from their website and customize it then it is shipped from China using UPS and spends almost a day in Alaska going through customs. Shipping is "free" but of course you are paying for it.
The freeway operator Citylink has been very tightlipped all morning however there is a growing whisper within the security industry in Melbourne that there weak security might have been breached from China.

I can't seem to comment in this thread for some reason so I'll update here: A friend just told me that network engineers from Europe are en route to Melbourne to assist in regaining control and that ASIO (Australian inernal security agency) is also now involved.
How to launch a startup
HANA vs Exadata X3 debate for in memory database
Everyone is an "X who Ys" for some value of X and Y. The question is what's your main job? If the answer is writing, reviewing, designing, or philosophizing about code, then your main job is software engineer. All three of the folks I mentioned fall in that category.

I had a friend in college who was extremely proud of his double major in biology and computer science. He went on to get a PhD in bioinformatics. He was fond of telling me that being "just a software engineer" would never be as exciting as the work he was doing in his specialized field (not going to go into details, but it was related to pharmaceuticals.)

A few years later, the pharmaceutical industry is in a slump and he can't find a job in his specialized field. So he's working on web design for a while, hacking PHP etc. I'm doing the same thing I've always been doing, working on distributed systems, and it's been very rewarding. (Before you ask, I did try to find a job for him, but he didn't want to move to the west coast.)

The moral of the story is to do what you really like and are good at, and don't worry about people telling you that you absolutely MUST shift your focus to X to succeed (where X = being a manager, being a quant, learning biology, etc).
Hi! I wrote this, and I've not heard of that before now... I'll check it out. It looks useful to me :)
> The gap between an hourly worker's wages in the US versus China is shrinking, due to Chinese labor inflation and US collar wage stagnation.

The system works!
The entire country ISN'T like that half of Baltimore.

Most of the country doesn't give a shit what color you are so long as you don't start with a presumptive "you're a fucking racist!" attitude.
That may be and I didn't mean to belittle how much work went into deciding what went on that page - but it is only one page that is responsive.
You are correct, sir, but if you press "restart" you forgo the "fast boot" hybrid and you do a cold boot. This is talked about in the article I reference on MSDN.

P.S - Picture viewer, Media Player, etc are still there, just not default. It's a pain.
The Chikyu is a (very large) riser drilling ship, not a robot. Other than that, dead on. The Chikyu was more or less built to drill the "mohole", and the Japenese government has been fairly set on it. However, it would almost definitely be a part of IODP (the Integrated Ocean Drilling Program), so the US would play a role in funding it, as well.
I didn't even know about Win+X (I knew you could right click the "start" tile, but this pretty awesome. Thank you :)
It's the default in rails
Yes, indeed. That's why we're finally seeing some sensibility being brought to JavaScript. He's bringing in basic features and functionality that should have been included 17 years ago, back when JavaScript was first developed.
Two pieces of advice.

1. Read. A lot! Some of the best salespeople in the world, the very best in their industries have written books. You can save yourself a lot of time by learning from the best. Commit to reading a sales related book a week, more if you can.

2. Spend as much time as possible in front of customers selling. Not preparing to sell, not going to sell, not travelling or pracitising.. just selling. It is like anything else, the more you do it the better you will get.

If you do just those two things you will become on of the best salespeople in your field. Not to mention the other benefits such as more confidence and money.
Hi! I use the built in Windows Defender since it does AV now. I don't see the point in slapping on another layer of protection since I don't tend to visit dodgy sites anyway.
Not "considered"... is. It's not just an interesting trivia tidbit, it's a fundamental part of the machine ceasing to be simply magic and becoming comprehensible. Everything is just numbers flying around.

Furthermore, if that's a revelation of some sort, or if you'd forgotten it, I'd commend to you a reading of any assembly language specification. Probably something simpler like MIPS or something, since in the end they are all the same w.r.t. the point I'm making here. I suggest this because it's important to see that at the very, very bottom of the machine, the very, very few things that the CPU can be truly said to be capable of, it's damn near "add, subtract, multiply, jump to some other instruction depending on the results of said", some instructions to fiddle with loading numbers from various places and a bit for receiving messages or interrupts when certain numbers arrive in certain places, and little else. There's no "display text" or "paint monster" instructions down there.

It's actually very important to understand this. It's really easy when studying assembler to not only correctly notice what is there, but to notice what isn't.
I don't think tabbed file browsing is necessary, but you're right, Microsoft is waaaay behind.
You can use the same strategy there too: in the signup page, it can just say "a confirmation email has been sent to your email". In the event that the email is already known, the email will say "someone else has tried to sign up with your email -- if this was you click here to change your password". This way, the attacker will never know if the email genuinely resulted in a new account or not.
There is, but it hasn't been created yet.

ConstantCrawl
I second this.

By the way, the law works through deterrence.

Say this is a douchebag workplace mistreating a douchebag employee, and they get punished.

Now they serve as example to the next douchebag workplace, who hesitate before mistreating their employee, who may not be a douchebag.
I'm not a fan of social login buttons, but I've visited a lot more brand pages on FB than I have product individual sites, usually because those FB pages are running a promotion where you "like" them and then fill in a form to get some product for free. Sometimes I'll unlike them afterwards, but sometimes I leave my "like" as-is. However, neither FB nor branded product sites have really influenced my purchasing decisions. What does? A product that I research via the web, consumer reports, or Amazon ratings and determine is good, a product that is on sale or is more attractive or just "looks" better (or maybe even has a higher price), and for services and applications, I do the same- look at reviews and determine if there is a free product or service that I feel comfortable using instead.

Marketing and ads are a HUGE con game, as people mostly ignore them.
Seriously, "true that", and that is why although most of my "day jobs" deal with Java, C is cooler, lol.
In addition to what the other reply stated, you also need to replace drillbits often, which would turn the drillbot into basically how drilling is done now.
Most ISPs don't change their IPs nearly that often. This isn't the 90s where everyone was dialing in, and changing an ip address would cause existing connections to fail, making the service look crappy. Most of the time the IP only changes when there's maintenance or something that requires it, or the modem gets disconnected.

Using a geolocation service isn't needed for the scenario you're replying to. If it was me, and I had this trolls ip, the first thing I would do it compare it to the other emails and connections that occurred simply to group the troll's crap together. In this situation the friend's email would have shown up to (being sent from the same house), and I doubt Mr. Traynor needed a geolocation service to look up the address of his friend.
wasn't there a shark tank where something similar was pitched? Thought he said he had patents protecting the idea, who knows what that covered

http://today.ucf.edu/ucf-engineering-alum-lands-500000-deal-...

http://abc.go.com/watch/shark-tank/SH559076/VD55203511/week-...
I am not old enough to state this with confidence, but I strongly suspect that a large minority, if not the majority, of people were in favour of McCarthyism in order to root out those awful communists. People are surprisingly unimaginative and just don't see how it could be turned on them.
Winamp was OK but crashed a little too often for me to be able to rely on it. DoubleTwist is, hands down, the worst music software I have installed on my laptop in recent memory (I can expand on this if you want, but my overall summary is: terrible). I hadn't tried WMP or Android Cloud Player, and at the time Google Music wasn't available to me. Spotify I haven't tried yet because until today, I couldn't even get it to see my phone despite my laptop and phone being on the same wireless network, as per the instructions. It has finally shown up though so I will give that a go.
Huh, it's as if white people come from a position of privilege, generations of near-total freedom from racial oppression, if you will, thus making similar-seeming actions have very different contexts!
Craigslist launches housing maps (wait for it to load)
Since the topic is Quora and startups of that ilk that are seeking funding, then my comment is completely accurate.

If you are starting a business and have no desire for outside funding, that is great. But if you go in knowing that you need outside funding and no one is interested, then you are in trouble. The situation of startups that hit the pavement seeking funding to no avail is all too common.
You're treating his every statement as suspect by default based on the racial, sexual and political stereotype you are projecting onto him.

The burden of proof for accusations of this nature (or any serious nature) should always be on the accuser, not the accused.
That's interesting, I didn't get the WWAN option so it's probably just dead space. Thanks!
Actually, it was simpler than that. The link on my ad went to a Fab.com sign up page that already had my referral code embedded. The user simply needed to make a purchase within the first 30 days to enable me to receive my referral credit. Many of the users I paid for most likely did buy something but not within the 30 day timeframe.
Kecak is fun, too: http://www.youtube.com/watch?v=0HL5P6wlQPU
I don't think you're going to see a reference implementation of resetting a password via SMS from NIST any time soon. They make standards for everybody. As soon as you start using words like database and email, you are ruling out lots of applications that don't have those features.
> Your comments comparing Rails and Drupal surprises me. I feel like you are writing without realizing how Rails development is done.

First, no offense taken.

Next, I do have a fair amount of experience developing in Rails (it's my go-to hobby framework and I MUCH prefer developing in it to Drupal as I thought I imparted in my original comment) and yes, there are gems that get you most of the way there with some of the tasks I described, but our site builders (read: non-developers) are unfamiliar with the command line, could not generally install gems without intervention from developers and, if necessary, could not extend them without developer intervention. That is what I'm trying to describe.

With Drupal, people who interact only with a web browser can install rich components from a library of modules developed by others with integration with the Content Types (basically the equivalent of Rails Models in Drupal) with zero development.

Looking back at my original comment, arguably my time estimates for development were exaggerated to some extent and could be shortened with the use of gems, but the fact remains there is, at current, no way for users, through only a web browser, to enable that kind of rich functionality in Rails. That was the point I was trying to get across.

You don't have to write much code but you still have to write code. This makes it a non-starter for a particular class of user.
All of these online communities face the same problem:

As they get bigger, the quality of the membership becomes severely diluted. Eventually, the crud fills the pages, the 'good' members leave, and all that remains is the crud.

This is happening on Quora too. Look at up-voted answers on non-tech questions. All it takes is a bunch of nicely formatted paragraphs, lists, bolded text, and a bunch of nice pictures. Tons of posters are commenting on places they have never visited and things they know nothing about.
Ask HN: Interest in a shared workspace in East Toronto?
I'm trying to get a group of like-minded hackers together to go in on a shared workspace in the East End of the city.

Ideally, I'd like to look at places along the Danforth, somewhere between Pape & Woodbine, though places south are OK too (the factories on Carlaw are about my southwest limit). In my head I see it running as a co-operative, on a strict cost-recovery basis, with frugalities like BYOD being likely; socializing & working with interesting people is the goal, not to make money. I'm hoping we could get enough people together that the monthly buy-in would be around $250 / mo / desk, but that's more a rough idea than anything concrete at this point.

If anyone is interested, the Toronto HN meetup on the 17th would be a great place to get to know one another (http://news.ycombinator.com/item?id=4585775)
OK, the other question might be: Who is visiting a Facebook page for toilet paper.

Question of a generation. I've had this same question in my head for a while; yes-social media can give you a very unique perspective into your customer base by way of what they like, who they're influenced by, et al.

But should you? "Who is visiting a Facebook page for toilet paper" might right off the cuff seem like a short, witty dismissive remark about a brand of toilet paper to some, but with the right pair of eyes you're able to see the deeper question: Just because social media is there, does that necessitate moving your brand to it?

I agree with everything you just said robomartin.
[EDIT: I misremembered my experience with Jetstrap -- of course the software actually exists, you can try it immediately. My apologies to the Jetstrap team]

[...]

How well do signups from HN correlate with actual paying customers? I recall a blog post from several years ago that concluded there were 10,000 people who would sign up for anything if it was featured on top tech aggregators.
I'm interested in buying carsabi as well as teaming up with developers. It needs a different model to make money and I know of a great one which I already developed. Contact me if you want to tackle the used car market.
Here's a fifth
One of them looks like a database from the student association. Most of their stuff is built by $9/hr work study so no big surprise it's insecure.
We already know how to drill them. It's how to keep producing heat out of them that's the problem. You need to circulate fluid _through_ a large volume of the rock, not just down the borehole. That means you need to create permeability (i.e. fracking. See "enhanced geothermal".) or find permeability at the depths required (i.e. find a reservoir). There are other problems, but the oil industry already developed most of the technology for other things. They've just decided that geothermal is a poor return on investment (in most cases) compared with producing and selling hydrocarbons. On the other hand, the world's largest geothermal energy producer is an oil company.
Who would've thought. Ironically, flying economy might someday save your life (if Economy Class Syndrome doesn't kill your first that is).
Sites that allow you to post public comments require a user name, so you're not forced to show your email address to everyone, while still allowing you to identify other users making comments. The best answer in these cases is to have both, and allow users to log in with either.
"... growing whisper within the security industry in Melbourne that there weak security might have been breached from China. ..."

Any idea what type of systems they are running?
I'm not selling anything here, just a friendly reminder to HN freelancers that you're probably not charging enough and you need to raise your rates.

Here's a friendly reminder of my own: be careful not to confuse anecdote with rule of law. Dangerous things can and do happen.
Sob story by a company that doesn't have a price? It seems to me that Jason Fried is talking about companies like this.
I've always found it helpful to explain a pointer as exactly that - a pointer, ie. a person standing there pointing at something.

If you need to keep track of something and know that no matter where you put him he's always going to be pointing at the same thing, sometimes it's going to be easier to move him around than, say, the 72-story building he's pointing at.

If you need to explain it more technically then the simple truth of them tracking the memory address of something has always seemed the best approach - then start learning what that actually means if need be. Anyone hoping to end up using C for much and not be shooting yourself in the foot constantly should be learning at least the basics of such things anyway.
Donald Eastman, President of Eckerd College in Florida wrote a great op ed piece on this subject a while back. It's worth a read http://awe.sm/d6AhQ

As a graduate of this small liberal arts school, I can relate to the power of "participating in learning communities, in which they [students] live, study and socialize with other learners."
Name-calling is definitely the right approach.

Did you know that in other countries healthcare is free? And top quality education? And college?

In no place anywhere on earth are those things free. Someone pays for them, always. Maybe the government should pay for them here (leaving aside the fact that our government already pays an enormous amount for healthcare and education), but it's not an obvious, incontrovertible fact that we should, to the point that justifies name-calling. Many top economists don't think those things should be subsidized by the government, regardless of how good they may sound to the electorate.

Also, you seem to be under the impression that incorporating in Delaware is some kind of tax dodge; it's not. It won't save you a single penny in taxes. You still have to pay taxes on income in the state in which you generate that income, and you still have to pay federal taxes no matter where you are in the world.
It's the jobless recovery
Ask HN: Providing support on side projects
For all of you who have side projects or ever had side projects, did you ever charge for them and if you did, how did you provide technical support outside your day job? I'm trying to build a Saas but I'm wondering how I would provide support given that I have a full time job.
While I have seen people walking around and trying doors, it's rare and it attracts a lot of attention. There's something of a herd immunity effect from door locking. As long as most doors are locked, a couple unlocked doors don't matter.

http://www.nytimes.com/2010/01/14/garden/14nolock.html?_r=0
>Furthermore, if that's a revelation of some sort... There's no "display text" or "paint monster" instructions down there.

Ouch. It wasn't. A little painful though after having studied computer engineering and even recently writing games in DCPU-16.

But anyway I will agree with most of what you said. The coolest part for me was always learning that there really was no magic underlying computers.

>Not "considered"... is.

My point is that everything in the computer being a number (large pieces of data being a single number) is just one of many interpretations and not a necessarily typical or useful one.

At bottom, everything in the computer is actually some configuration of electrons. But it's not very useful to work conceptually at the level either.
The product exists, you can sign up and play with it. Is there something we could do to make that more clear?